Portable devices are ubiquitous in present day. People use portable devices for performing variety of such as wireless communication, data computing, surfing the Internet, running specialised applications, gaming, etc. Portable devices include but are not limited to mobile phones, tablet computers, laptop PC's, PDA's, etc.
Due to the size of these portable devices, the power source for these devices, e.g., an internal battery, is often small and of limited capacity. As a result, the battery of a portable device may have to be frequently charged in order to keep the portable device operational. Depending on the amount of charge an internal battery of a portable device is designed to handle, the charging time for the battery may range from 1-2 hours to over 12 hours. The main reason being the voltage (and consequently the current) used to charge these portable devise is usually less than to close to 5 V, which results in longer charging time. As the demand for higher capacity batteries in portable devices increases, the charging times will get longer.